Method for assembling refrigeration systems



1957 E. L. AUGUSTAUSKAS 2,782,496

METHOD FOR ASSEMBLING REFRIGERATION SYSTEMS Filed April 8, 1954 FIG.|

23 INVENTOR.

EDWARD L. AUGUSTAUSKAS HIS ATTORNEY METHOD FOR ASSEMBLING REFRIGERATION SYSTEMS Edward L. Augustauskas, Erie, Pa., assignor to General Electric Company, a corporation of New York Application April 8, 1954, Serial No. 421,729

7 Claims. (Cl. 29-469) My invention relates to refrigerating systems and more particularly to methods for assembling such systems.

In the manufacture of household refrigerators, the refrigerating systems are ordinarily assembled into complete units and are then evacuated of air and charged with refrigerant before being placed in the refrigerator cabinets. However, due to the size of the complete systems and the length of the tubing contained therein the evacuation process can present considerable difficulties. The bulk of the systems make them difficult to handle during the bake-out step which is customarily part ofthe evacuation process; and the long and tortuous path presented by each complete system makes it difficult to remove all the air therefrom. Specifically the serpentine paths of the evaporator often make it particularly difiicu'lt to evacuate when it is connected in the complete system.

Accordingly, it is an object of my invention to provide a new and improved method for assembling a refrigeration system.

It is another object of my invention to provide a new and improved method for assembling a refrigeration system in which the condensing unit section and the evaporator section are evacuated separately and are then placed in communication to complete the system.

It is a further object of my invention to provide a new and improved method for assembling a refrigeration system in which the condensing unit section and the evaporator section are first evacuated separately and are then placed in communication to complete the system, with the means allowing the separate evacuation and the later communication being effectively disposed of so that no restriction is left in the system to impede refrigerant flow after communication has been established.

In carrying out my invention in one preferred manner thereof, I connect the various components of the refrigeration system to be assembled into an evaporator section and a condensing unit section. The ends of at least one of these separate sections or assemblies are then closed by fusible plugs. The two assemblies are connected and sealed together with the plugs preventing any communication therebetween, and they are separately evacuated with at least the aforesaid one assembly being evacuated prior to its connection to the other assembly. The plugs are then melted to effect communication between the evacuated assemblies and thereby a complete evacuated system is formed without leakage of air thereinto. Preferably the tubes containing the fusible plugs are maintained in an inclined position during the melting to cause the melt to be deposited over a length of the tubes, whereby the melt after solidification is not restrictive of flow within the system. To most effectively dispose of the melt, however, recessed pockets are provided in the sides of the tube wherein the melt may flow and solidify completely out of the path of refrigerant flow.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims. My invention, however, may be best understood by reference to the following description to ited States Patent 2,782,496 Patented Feb. 26, 1957 be taken in conjunction with the accompanying drawing in which:

Fig. l is a schematic showing of a refrigeration system assembled according to my new and improved method;

Fig. 2 is a fragmentary sectional view showing how the ends of the evaporator and condensing unit sections of the system are brought together to be assembled;

Fig. 3 is a fragmentary sectional view showing how the plugs at the ends of the sections are melted to place the two sections in communication;

Fig. 4 is a view similar to Fig. 3 showing the unrestricted passage left by the melting of the plugs;

Fig. 5 is a fragmentary sectional View of tubes including a novel means for disposing of the molten material or melt from the plugs.

Fig. 6 is a fragmentary sectional view of tubes including an alternate means for disposing of the melt.

Referring now to Fig. l I have shown therein a refrigeration system of the type which may be assembled according to my new and improved method. In assembling this system the first step in my method is to assemble the various components of the system into an evaporator section and a condensing unit section so that the system may be evacuated, and if desired charged, in two parts rather than as one large unit. Specifically in the illustrated system the evaporator 1, the suction tube 2, the capillary 3, and a capillary inlet tube or adaptor 4 are connected together to form the evaporator section or assembly. Similarly, the compressor 5, the compressor inlet tube 6, the compressor outlet tube 7, the condenser 8 and the condenser outlet tube 9 are all connected together to form the condensing unit section or assembly. Since the two assemblies each are only half of a complete refrigeration system, they are, of course, much less bulky than the entire system and thus much easier to handle and evacuate than the entire system.

In order that they may be separately evacuated, and if desired separately charged, before being assembled together, the ends of the condensing unit assembly and the evaporator assembly are next closed off or plugged. In accordance with my invention, this plugging is accomplished by means of fusible plugs which may be melted at a temperature lower than that at which the tube ends themselves would melt. Various solders or brazing materials may be used to make these plugs but the preferred material is a brazing compound formed of 15% silver, copper, and 5% phosphorous. This compound has a melting point in the order of l,l F. and a flow point of about l,300 F. Both the melting point and the flow point are well below that of copper of which the condenser and evaporator tubing are ordinarily formed.

In my preferred method the ends of the one assembly are enlarged for a distance so that the ends of the other assembly may be inserted thereinto in a sleeve-like arrangement. Thus in my preferred assembly the ends of tubes 2 and 4 associated with the evaporator are enlarged so as to accommodate the ends of tubes 6 and 9 included in the condensing unit assembly. The smaller tubes 6 and 9 are plugged at their very ends, whereas the tubes 2 and 4, whose ends form the surrounding sleeves, are plugged somewhat back from their ends. This may be seen by reference to Fig. 2 wherein the plug it is shown as closing the tube 6 at its very end, and the plug 11 is shown as closing the tube 2 inwardly from its end at the point where its enlarged portion 12 begins.

Once the plugs have been placed in position as shown, the two assemblies may then be baked out and evacuated separately. The plugs form air-tight seals effectively preventing leakage into the two assemblies. The valve means whereby this evacuation is accomplished in the two assemblies are not shown, since any suitable valve means may be used. The assemblies may also be charged separately with refrigerant after their evacuation, and although such is not done in my preferred method, it should be understood that I contemplate such procedure and that it may be followed without departing from my invention. In fact, as used hereinafter both in the description and in claims, it will be understood that the term evacuated is not meant to restrict my invention to a method wherein the assemblies are only evacuated and not charged separately.

Once the two assemblies have been evacuated they are then connected together so as to form a complete refrigeration system. To do this the. tube 6 is inserted within the tube 2 and the tube 9 is inserted within the tube 4 until their respective plugs abut against each other. The manner in which these plugs abut against each other may be clearly seen in Fig. 3. Considering now only tubes 2 and 6 since exactly the same process takes place with respect to the tubes 4 and 9, it will be seen that as the tube 6 is inserted into the end of tube 2 the air remaining between plug 11 and the end of tube 2 is pushed outwardly as tube 6 is inserted. By the time the plug 10 is brought into contact with plug 11 only a very minute amount of air will remain between the plug 11 and the end of tube 2. This sleeve-like arrangement is, however, not the only manner in which the tubes can be connected together. For example one alternate way is to provide flanges at the ends of the tubes and then join together these flanges.

Whatever manner is used, however, once the tubes have been joined together so as to bring the plugs in contact, they are then connected together by means of an air-tight seal. Thus as shown in Fig. 3 the end of tube 2 is connected to tube 6 by an air-tight joint 13. This joint or seal 13 may be made by any suitable brazing material. Once the two assemblies have been so sealed together the only step remaining to complete the entire assembly of the system is to place the two assemblies in communication. This is done by applying heat to the tubes so as to melt the fusible plugs. Thus as is shown in Figs. 3 and 4 a hot flame may be applied to the tubes so as to cause melting of the plugs. However, it should be understood that this heating could be done by electrical or other means if desired. The point at which the plugs come into abutment and thus at which the heat is applied lies down the tubes a distance from the joint or seal 13. This distance which is preferably equal to or greater than three diameters of the inner tube is necessary in order to prevent melting of the seal 13 when the fusible plugs themselves are melted. By spacing the melting point from the seal 13 suflicient heat will not be conducted through the tubes to cause melting of the seal.

Preferably the tubes are held in a slanted or inclined position while the plugs are fused or melted. This is done so that as the plugs are melted, the melt will be deposited over a length of the tubes. In other words as the plugs are turned into a molten state, the liquid melt tends to flow along the tube a distance before solidifying, andthus is not all deposited at one place. This may be seen by reference to Fig. 4 wherein a thin coating of melt 14 is shown as deposited over a fairly long length of the tube 2 as a result of the melting of the plugs 10 and 11. This thin layer of melt does not offer any appreciable restriction to flow of refrigerant in the system once it is put in operation.

By the melting of the plugs the two evacuated assemblies are placed in communication with each other to form a complete evacuated system. Since as mentioned above they were scaled together prior to the fusing of the plugs, the fusing will not cause any air leakage into the system. Thus, according to my invention, the evaporator assembly and the condensing unit assembly may be evacuated separately and later assembled together to form a complete system without any appreciable loss of vacuum.

In the above description of my preferred method the condensing unit section or assembly and the evaporator section or assembly are baked-out and evacuated separate- 'the bottom surface of tube into the pocket 17.

1y before being assembled together. However, it may at times be desirable to bake out and evacuate only one of these assemblies before connecting it to the other. If this is done it would be necessary to plug only that one assembly with my fusible plugs. After it has been evacuated, it may then be connected to the other assembly and its plugs will be sufficient to prevent any communication therebetween. The second assembly may then be baked out and evacuated after connection and finally the plugs of the first assembly fused to complete the system.

Referring now to Figs. 5 and 6 I have shown therein improved means for disposing of the melt from the fusible plugs. Thus in Fig. 5 there is shown a tube 15 forming the end of an evaporator assembly and a tube 16 forming the end of a condensing unit assembly. In accordance with my invention the tube 16 has included therein a recessed pocket or depression 17. This pocket 17 is located adjacent the point 18 whereat the fusible plugs are positioned prior to their being melted. The tubes 15 and 16 are inclined or slanted during the melting of plugs and thereby the melt tends to run downwardly along This pocket 17 accommodates practically all of the melt so that not even a thin layer of it is formed along the tube, and thus practically no restriction at all can result from the melting of the fusible plugs.

Referring now to Fig. 6 I have shown therein an alternate means for catching the melt resulting from the fusing of the plugs. In Fig. 6 a tube 19 forming part of a condensing unit assembly is shown as inserted in a tube 20 forming part of an evaporator assembly. The tube 20 includes a crook or elbow 21 adjacent the point 22 at which the fusible plugs are positioned prior to their being melted. The elbow 21 includes therein a pocket or extension 23 which lies substantially out of the path of refrigerant flow through the tube. The tubes 19 and 20 are maintained in an inclined position as the plugs are fused and therefore the melt runs downwardly along the bottom surface of tube 20 into the pocket 23. This pocket 23 is large enough to accommodate substantially all of the melt so that only the very small portion of the melt which solidifies before reaching the pocket remains to restrict the refrigerant flow, and that restriction is practically negligible.

Summing up, it may be seen that through my invention I have provided a new and improved method whereby the various assemblies of a refrigeration system may be evacuated, and if desired charged, before being connected together to complete the system. The use of my fusible plugs allows the assemblies to be evacuated separately and later placed in communication without any appreciable restriction remaining to the flow of refrigerant within the system. Further, the fusing of the plugs effects the communication between the system without any appreciable leakage of the air thereinto.

In accordance with the patent statutes I have described what at present is considered to be the preferred manner of accomplishing my invention. However, it should be understood by those skilled in the art that various changes and modifications may be made therein without departing from my invention, and I, therefore, aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. The method of assembling an evacuated refrigeration system which comprises connecting the components of the system into an evaporator assembly and a condensing unit assembly, closing the end tubes of at least one of said assemblies by fusible plugs, connecting and sealing together said assemblies with said plugs preventing communication therebetween, separately evacuating said assemblies with at least said one assembly being evacuated prior to its connection to the other of said assemblies,

melting said plugs to effect communication between said assemblies whereby a complete evacuated system is formed without leakage of air thereinto, and maintaining the end tubes of said assemblies in an inclined position during the melting to cause the melt from the plugs to be deposited over a length of said tubes whereby the deposited melt is not restrictive of flow within the system.

2. The method of assembling an evacuated refrigeration system which comprises connecting the components of the system into an evaporator assembly and a condensing unit assembly with the end tubes of a predetermined of said assemblies including recessed pockets in the inner surfaces thereof, closing the end tubes of at least one of said assemblies by fusible plugs, connecting and sealing together said assemblies with said plugs preventing communication therebetween, eparately evacuating said assemblies with at least said one assembly being evacuated prior to its connection to the other of said assemblies, melting said plugs to efiect communication between said assemblies whereby a complete evacuated system is formed without leakage of air thereinto, and maintaining the end tubes of said assemblies in an inclined position during the melting to cause the melt from said plugs to be deposited in said recessed pockets whereby the deposited melt is not restrictive of flow within the system.

3. The method of assembling an evacuated refrigeration system which comprises connecting the components of the system into an evaporator assembly and a condensing unit assembly with the end tubes of a predetermined of said assemblies including a recessed elbow section, closing the end tubes of at least one of said assemblies by fusible plugs, connecting and sealing together said assemblies with said plugs preventing communication therebetween, separately evacuating said assemblies with at least said one assembly being evacuated prior to its connection to the other of said assemblies, melting said plugs to elfect communication between said assemblies thereby to form a complete evacuated system without leakage of air thereinto, and maintaining the end tubes of said assemblies in an inclined position during the melting to cause the melt from said plugs to be deposited in said recessed elbow sect-ions whereby the deposited melt is not restrictive of flow within the system.

4. The method of assembling an evacuated refrigeration system which comprises connecting the components of the system into an evaporator assembly and a condensing unit assembly, closing the ends of said assemblies by means of fusible plugs, separately evacuating said assemblies, connecting said ends of said assemblies to place the fusible plugs of one assembly in abutting relation with said fusible plugs of the other of said assemblies, sealing together said ends of said assemblies, and apply ing heat to melt said plugs and effect communication between said assemblies whereby the complete refrigeration system is formed without leakage of air thereinto.

5. The method of assembling an evacuated refrigeration system which comprises connecting the components of the system into an evaporator assembly and a condensing unit assembly, closing the end tubes of said assemblies by means of fusible plugs, separately evacuating said assemblies, connecting said end tubes of said assemblies to place said fusible plugs of one assembly in abutting relation with said fusible plugs of the other assembly, sealing together said end tubes of said assemblies, applying heat to melt said plugs and effect communication between said assemblies thereby to form a complete evacuated system without leakage of air thereinto, and maintaining said tubes in an inclined position during the melting to cause the melt from said plugs to be deposited over a length of said end tubes whereby the deposited melt is not restrictive of flow within the system.

6. The method of assembling an evacuated refrigeration system which comprises connecting the components of the system into an evaporator assembly and a condensing unit assembly with the end tubes of at least one of said assemblies including recessed pockets in the inner surface thereof, closing the end tubes of said assemblies by means of fusible plugs, separately evacuating said assemblies, connecting said end tubes of said assemblies to place said fusible plugs of one of said assemblies in abutting relation with said fusible plugs of the other of said assemblies, sealing together said end tubes of said assemblies, applying heat to melt said plugs and eifect communication between said assemblies thereby to form a complete refrigeration system, and maintaining said tubes in an inclined position during the melting to cause the melt from the plugs to be deposited in said recessed pockets thereby the deposited melt is not restrictive of flow within the system.

7. The method of assembling an evacuated refrigeration system which comprises connecting the components of the system into an evaporator assembly and a condensing unit assembly with the end tubes of at least one of said assemblies including a recessed elbow section, closing the end tubes of said assemblies by means of fusible plugs, separately evacuating said assemblies, conmeeting together said end tubes of said assemblies to place said fusible plugs of one of said assemblies in abutting relation with said fusible plugs of the other of said assemblies, sealing together said end tubes of said assemblies, applying heat to melt said plugs and effect communication between said assemblies thereby to form a complete refrigeration system Without leakage of air thereinto, and maintaining said tubes in an inclined position during the melting to cause the melt from said plugs to be deposited in said recessed elbow sections whereby the deposited melt is not restrictive of flow within the tube.

References Cited in the file of this patent UNITED STATES PATENTS 1,844,367 Pirani Feb. 9, 1932 1,921,809 Crain Aug. 8, 1933 2,338,953 Melke Jan. 11, 1944 2,457,599 Pessel Dec. 28, 1948 2,485,444 Hofberg Oct. 18, 1949 2,649,993 Burdick Aug. 25, 1953 2,667,760 Curtis Feb. 2, 1954 

